1. Field of the Invention
The present invention relates to a liquid crystal display device for vehicle use, the device having a liquid crystal display and a cover member covering the periphery of the liquid crystal display. When the liquid crystal display is not used, a screen disposed in the front of a display surface of the liquid crystal display can be made inconspicuous.
2. Description of the Related Art
Recently, a liquid crystal display device has been proposed for an instrument panel, vehicle seat or the like. On a liquid crystal display assembled in the instrument panel, map information of a car navigation system, an audio operation picture, DVD pictures and the like are displayed. In the case of a liquid crystal display assembled in the vehicle seat, the liquid crystal display is situated at a rear face side of a seatback or a headrest, and the pictures and the like can be enjoyed from a rear seat. For example, a liquid crystal display device for vehicle seat, as shown in JP-A-2007-238005. And, a liquid crystal display device for instrument panel, as shown in JP-A-2001-331132.
The liquid crystal display device of JP-A-2007-238005 uses a typical liquid crystal display having a display surface attached with polarization means including a polarizing film or polarizing plate. The display surface attached with the polarization means is exposed to the outside. In this case, a cover member is set such that it covers a display frame. Therefore, a difference in level is formed between the cover member and the liquid crystal display, and therefore the display surface is by one step from a surface of the cover member. Therefore, particularly when the liquid crystal display is not used, the device lacks in physical integration feeling between the display surface of the liquid crystal display and the cover member enclosing the display surface, leading to a problem in design quality. As a solution of this, a screen disposed in the same level as the cover member is considered to be used. However, in this case, the screen is further required to have color integration with the cover member. Consequently, if a transparent screen is merely used, since the internal liquid crystal display can be viewed from the outside through the screen when it is not used, a problem remains in color integration feeling.
On the other hand, in the liquid crystal display device of JP-A-2001-331132, polarization means is attached on a display surface, in addition, a screen is disposed in the front of the display surface. When the device is not used, the screen is inconspicuous and has an integrated feeling with peripheral members, and when it is used, various kinds of information can be viewed through the screen. The screen is made such that a smoke sheet is attached on a surface of a diffuser sheet, and a woodgrain pattern having many micropores that can transmit display light is formed on a surface of the smoke sheet. When the liquid crystal display is not used, the smoke sheet shades part of light from the outside, and therefore the inside of the device cannot be viewed through the screen. In addition, the same woodgrain pattern as that of the instrument panel is formed on the smoke sheet, so that an integrated feeling with the instrument panel is improved. When the liquid crystal display is used, a displayed image is viewed through the smoke sheet and the micropores of the woodgrain pattern. However, level equalization between the screen and the instrument panel is not particularly considered, and therefore lack of a physically integrated feeling is a concern. Moreover, since an image needs to be displayed through the smoke member in addition to the polarization means, luminance of a backlight of the liquid crystal display has to be increased compared with that in a usual case. Moreover, while the polarizing film or the like is typically subjected to antireflection processing, the screen still needs to be subjected to antireflection processing in order to display a clear image, causing a problem in cost. That is, since the liquid crystal display device uses a separated member (screen) from the polarization means, the device has a problem that the smoke member needs to be used, or a problem that additional processing is needed.
Thus, there is a need in the art for a liquid crystal display device for vehicle use, wherein even if the quantity of light is not increased, or additional processing is not performed, difference in level from the periphery is not found, and color integration feeling with the periphery is given, leading to high design quality.